The dependence of paracetamol absorption on the rate of gastric emptying

Abstract

1 The rate of gastric emptying was measured directly in 14 convalescent hospital patients and paracetamol absorption was studied following an oral dose of 1·5 g. 2 Rapid gastric emptying was associated with the early appearance of high peak plasma paracetamol concentrations whereas peak concentrations were low and occurred late when gastric emptying was slow. 3 There was a significant correlation between the rate of gastric emptying and the 0·4 and 0·24 h urinary excretion of paracetamol and its metabolites. 4 In five patients with abnormally slow gastric emptying the mean maximum plasma concentration and 0·4 and 0·24 h urinary excretion of paracetamol were significantly lower than in seven patients with normal gastric emptying rates while the time taken to reach maximum plasma concentrations was longer. 5 Individual differences in the rate of gastric emptying may contribute to variable absorption of many drugs.